IARPE - AGS

Alternating Gradient Synchrotron

News from AGS

The AGS is nearing the end of a four month shutdown. There has been less radiological work than expected. This is mostly due to increasingly significant efforts being expended at getting the Relativistic Heavy Ion Collider read for commissioning in 1999. One large AGS undertaking has been the re-design of the C3 beam line. Historically, due to poor beam transport optics, the water-cooled magnets in this line have experienced heavy activation. In turn, the magnet water, most of which is recirculated to a cooling tower outside of the experimental building, has been responsible for a small cooling tower plume containing the short-lived radiogases C-11, N-13, and O-15. This plume has proven to be a nuisance to other on-site operations as the AGS's intensity has surged in recent years. For example, when the wind is from the north and the AGS is operating at high intensity, the High Flux Beam Reactor portal monitors, to the south of the AGS, will periodically alarm.

In order to reduce emissions from this cooling tower, the AGS has instituted several measures such as the inclusion of a closed loop heat exchanger which prevents some primary magnet water from being recirculated to the cooling tower. As mentioned above, the C3 line upgrade is expected to further reduce emissions by installing a copper collimator. The collimator's main job will be to reduce the activation rate of downstream magnets from the beam halo. Its cooling water will also be placed on the closed loop heat exchanger. Additional C3 magnet cooling water will likewise be placed on the same closed loop heat exchanger. These improvements are expected to lower the cooling tower radio gas emissions by a factor of three.

The AGS is also expected to approve the design of a beam scraper which will be placed in a less traveled area of the main ring. The scraper's design is supposed to allow for essentially all ring activation to occur at one point, rather than being spread out over many loss points. This project has been primarily motivated by the ongoing concern of keeping radiation doses as low as reasonably achievable. Presently, most of the activation occurs in the extraction magnets. Repeated failures in several of these elements have caused heavy doses to be incurred during repairs. The beam scraper will be well shielded and water-cooled. Installation is expected later this year.

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